Exhibit 2.2

                           PURCHASE AND SALE AGREEMENT

                      JOHN HANCOCK LIFE INSURANCE COMPANY,
                                     SELLER

                                       AND

              BEACON CAPITAL STRATEGIC PARTNERS II ACQUISITION, LLC
                                    PURCHASER
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                                TABLE OF CONTENTS

1.    The Property............................................................ 1

       1.1      Description................................................... 1
       1.1A     Sublease...................................................... 3
       1.2.     "As-Is" Purchase.............................................. 3
       1.3.     Agreement to Convey........................................... 4

2.    Price and Payment....................................................... 4

       2.1      Purchase Price and Payment of Initial Rent.................... 4
       2.2      Payment....................................................... 4
       2.1      Closing....................................................... 5

3.    Inspections and Approvals............................................... 5

       3.1.     Access........................................................ 5
       3.2.     Title and Survey.............................................. 5
       3.3.     Contracts..................................................... 6
       3.4.     Permitted Exceptions.......................................... 6
       3.5.     Intentionally Omitted......................................... 7
       3.6.     Confidentiality............................................... 7

4.    Prior to Closing........................................................ 8

       4.1.     Intentionally Omitted......................................... 8
       4.2.     Intentionally Omitted......................................... 8
       4.3.     Intentionally Omitted......................................... 8
       4.4.     New Leases.................................................... 8
       4.5.     Capital Work.................................................. 8
       4.6.     Tenant Estoppel Certificates.................................. 8
       4.7.     Subordination, Non-disturbance and Attornment Agreements...... 9

5.    Representations and Warranties.......................................... 9

       5.1.     By Seller..................................................... 9
       5.2.     By Purchaser................................................. 12
       5.3.     By Broker.................................................... 12
       5.4.     Seller's Knowledge........................................... 13
       5.5.     Effect of Tenant Estoppel Certificate........................ 13
       5.6.     No Representation as to Leases............................... 13
       5.7.     Seller's Warranties Deemed Modified.......................... 13
       5.8.     Limitation of Representations................................ 13
       5.9.     Survival; Limitation on Seller's Liability................... 14


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6.    Costs and Prorations................................................... 14

       6.2.     Seller's Cost................................................ 15
       6.3.     Other Closing Costs.......................................... 15
       6.4.     Prorations................................................... 15
       6.5.     Purpose and Intent........................................... 18

7.    Damage, Destruction or Condemnation.................................... 18

       7.1.     Intentionally Omitted........................................ 18
       7.2.     Intentionally Omitted........................................ 18
       7.3.     Intentionally Omitted........................................ 18

8.    Notices................................................................ 18


9.    Closing and Escrow..................................................... 20

       9.1.     Escrow Instructions.......................................... 20
       9.2.     Seller's Deliveries.......................................... 20
       9.3.     Purchaser's Deliveries....................................... 22
       9.4.     Possession................................................... 22

10.   Default; Failure of Condition.......................................... 22

       10.1.    Intentionally Omitted........................................ 22
       10.2.    Intentionally Omitted........................................ 22
       10.3.    Conditions to Purchaser's Obligations........................ 23
       10.4.    Conditions to Seller's Obligations........................... 23

11.   Miscellaneous.......................................................... 23

       11.1.    Entire Agreement............................................. 23
       11.2.    Severability................................................. 24
       11.3.    Applicable Law............................................... 24
       11.4.    Assignability................................................ 24
       11.5.    Successors Bound............................................. 24
       11.6.    No Public Disclosure......................................... 24
       11.7.    Captions..................................................... 24
       11.8.    No Partnership............................................... 25
       11.9.    Time of Essence.............................................. 25
       11.10.   Counterparts................................................. 25
       11.11.   Recordation.................................................. 25
       11.12.   Proper Execution............................................. 25
       11.13.   Tax Protest.................................................. 25
       11.14.   Intentionally Omitted........................................ 25
       11.15.   Intentionally Omitted........................................ 25


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       11.16.   Liability of Seller.......................................... 25
       11.17.   Waiver....................................................... 25
       11.18.   Seller's Performance......................................... 25
       11.19.   Title Company................................................ 26
       11.20.   Further Assurances........................................... 26
       11.21.   Intentionally Omitted........................................ 26
       11.22.   Air Rights Lease............................................. 26


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                           PURCHASE AND SALE AGREEMENT

            THIS AGREEMENT (the "Agreement"), dated as of the __________ day of
__________ 2003, is made by and between JOHN HANCOCK LIFE INSURANCE COMPANY, a
Massachusetts corporation ("Seller"), having an office at 200 Clarendon Street,
Boston, Massachusetts 02117, and BEACON CAPITAL STRATEGIC PARTNERS II
ACQUISITION, LLC, a Delaware limited liability company ("Purchaser"), having an
office at One Federal Street, 26th Floor, Boston, Massachusetts 02110.

                                    RECITALS:

      Seller desires to sell certain improved real properties in Boston,
Massachusetts, including the property known as 200 Clarendon Street or the John
Hancock Tower (the "Tower"), the property known as 200 Berkeley Street (the
"Berkeley Building"), the property known as 197 Clarendon Street (the "Brown
Building"), and to sublease certain of Seller's interest as tenant under an air
rights lease and as owner of the improvements thereon known as 155 Dartmouth
Street and 100 Clarendon Street or the John Hancock Garage (the "Garage"), along
with certain related personal and intangible property, and Purchaser desires to
purchase and sublease such real, personal and intangible property.

      NOW, THEREFORE, in consideration of the foregoing, of the covenants,
promises and undertakings set forth herein, and for good and valuable
consideration, the receipt and sufficiency of which is hereby acknowledged,
Seller and Purchaser agree as follows:

1. The Property.

      1.1. Description. Subject to the terms and conditions of this Agreement,
and for the consideration herein set forth, Seller agrees to sell and transfer,
and Purchaser agrees to purchase and acquire, all of Seller's right, title and
interest in and to the following (collectively, the "Property"): --------

            1.1.1 Certain land (the "Land") located in Boston, Massachusetts,
and more specifically described in Exhibit 1.1.1 attached hereto;

            1.1.2 INTENTIONALLY OMITTED

            1.1.3 The rights, if any, appurtenant to the land set forth in (a)
the Declaration of Easements and Shared Facilities Agreement, the form of which
is attached hereto as Exhibit 1.1.3 (the "Easement and Facilities Agreement")
and (b) the Easement Agreement, the form of which is attached hereto as Exhibit
1.1.3-1 (the "Easement Agreement") (the easements set forth in Easement and
Facilities Agreement and the Easement Agreement, collectively, the "Easements");

            1.1.4 Except as expressly limited in this Agreement, the Buildings
(the "Buildings"), parking areas, improvements, and fixtures now situated on the
Land (the "Improvements") (the Land, the Easements and Improvements being the
"Real Property");


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            1.1.5 All furniture, personal property, machinery, apparatus, and
equipment owned by Seller or leased to Seller and currently used in the
operation, repair and maintenance of the Land, Leasehold and the Improvements
and situated thereon, excluding, however, tangible personal property and
fixtures of the Improvements which are owned by tenants, licensees, the operator
of the Garage and other third parties or which may be removed by such parties
under the terms of their leases (collectively, the "Personal Property"), and
expressly excluding (x) personal property, trade fixtures and equipment used by
Seller in its business operations to the extent located within that portion of
the Property leased to an affiliate of Seller pursuant to an Affiliate Lease as
more particularly described in paragraph 1 of Exhibit 1.1.5 and (y) those items
listed as "Excluded Property" in Exhibit 1.1.5 (but expressly including (i) such
property described as "Included Property" in Exhibit 1.1.5, (ii) all property,
furniture and equipment relating to the operation and maintenance of the
cafeteria (including without limitation any property, furniture and equipment
currently supplied by Seller pursuant to that certain Food Service Agreement,
dated as of January 1, 2003, between Seller and Guckenheimer Enterprises, Inc.
(the "Cafeteria Agreement")) and (iii) all replacement glass panels for the
Tower and all other property and equipment related thereto). The Personal
Property to be conveyed is subject to depletions, replacements and additions in
the ordinary course of Seller's business;

            1.1.6 All easements, licenses, hereditaments, and appurtenances
belonging to or inuring to the benefit of Seller and pertaining to the Land, if
any;

            1.1.7 Any street or road abutting the Land to the center line
thereof;

            1.1.8 The leases, licenses, concessions, antennae site agreements or
occupancy agreements in effect on the date of this Agreement, including, without
limitation, those which are identified on the Schedule of Leases attached hereto
as Exhibit 1.1.8, which as of the Closing (hereinafter defined) affect all or
any portion of the Land or the Improvements, (collectively, the "Leases"), and
any Security Deposits (as hereinafter defined) actually held by Seller with
respect to any such Leases;

            1.1.9 Subject to Section 3.3, all Contracts (hereinafter defined)
having terms which extend beyond midnight of the day preceding the Date of
Closing (hereinafter defined);

            1.1.10 Assignable warranties and guaranties issued in connection
with the Improvements or the Personal Property which remain in effect as of
Closing (hereinafter defined); and

            1.1.11 All transferable consents, authorizations, variances or
waivers, licenses, permits and approvals from any governmental or
quasi-governmental agency, department, board, commission, bureau or other entity
or instrumentality in respect of the Real Property or the Improvements which
remain valid or in effect as of Closing (collectively, the "Approvals").

            The term "Property" expressly excludes all matters expressly
reserved to Seller in one or more Property Restrictions & Trademark License
Agreements substantially


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in the form attached hereto as Exhibit 1.1.10 (collectively, the "Naming
Agreement"). The terms and provisions of this paragraph shall survive Closing
hereunder or termination of this Agreement.

            1.1A Sublease. Subject to the terms and conditions of this
Agreement, and for the consideration hereinafter set forth, Seller and Purchaser
agree to enter into a sublease with respect to a portion of the interest of
Seller as tenant under that certain lease between the Massachusetts Turnpike
Authority (the "MTA") and John Hancock Mutual Life Insurance Company (n/k/a John
Hancock Life Insurance Company) dated May 1, 1969, (the "Air Rights Lease"), all
on the terms set forth in the form of sublease attached hereto as Exhibit 1.1A
(the "Sublease") (the premises described therein which is subleased to Purchaser
being hereinafter referred to as the "Sublease Premises"). For purposes of this
Agreement, the term Property shall include the Sublease Premises and appurtenant
rights described in the Sublease and the real property and appurtenant rights to
be conveyed or transferred pursuant to Section 11.22 (the latter collectively
being the "Adjoining Parcel"); the term Contracts shall include those Contracts
attributable to the Sublease Premises listed on Exhibit 3.3; and the term Leases
shall include those leases, licenses, occupancy agreements and parking rights
attributable to the Sublease Premises and which are listed on Exhibit 1.1.8.

      1.2. "As-Is" Purchase.

            (a) The Property is being sold in an "AS IS, WHERE IS" condition and
"WITH ALL FAULTS". Except for Seller's Warranties (as defined in Section 5.9),
no representations or warranties, express, implied or arising by operation of
law, have been made or are made and no responsibility has been or is assumed by
Seller or by any partner, officer, person, firm, agent, attorney, or
representative acting or purporting to act on behalf of Seller as to the
condition or repair of the Property or the value, expense of operation, or
income potential thereof or as to any other fact or condition which has or might
affect the Property or the condition, repair, value, expense of operation or
income potential of the Property or any portion thereof. The parties agree that
all understandings and agreements heretofore made between them or their
respective agents or representatives are merged in this Agreement and the
Exhibits hereto annexed, which, along with any confidentiality agreements or
access agreements that have been or may be entered into between the parties,
alone fully and completely express their agreement, and that this Agreement has
been entered into after full investigation, or with the parties satisfied with
the opportunity afforded for investigation, neither party relying upon any
statement or representation by the other unless such statement or representation
is specifically embodied in this Agreement or the Exhibits annexed hereto.
Except for Seller's Warranties (as defined in Section 5.9 below), Seller makes
no representations or warranties as to whether the Property contains asbestos or
any hazardous materials or harmful or toxic substances, or pertaining to the
extent, location or nature of same, if any. Further, to the extent that Seller
has provided to Purchaser access or use of a physical or electronic data room or
internet site (any such form of access or use referred to as "Data Room") or
information from any inspection, engineering or environmental reports concerning
asbestos or any hazardous materials or harmful or toxic substances, Seller makes
no representations or warranties with respect to the accuracy or completeness,
methodology of preparation or otherwise concerning the contents of such Data


                                       -3-
<PAGE>

Room or reports. Purchaser acknowledges that Seller has requested that Purchaser
inspect the Property fully and carefully and investigate all matters relevant
thereto and that Purchaser rely solely upon the results of Purchaser's own
inspections or information obtained or otherwise available to Purchaser, rather
than any information that may have been provided by Seller to Purchaser.
Purchaser expressly understands and acknowledges that it is possible that
unknown liabilities may exist with respect to the Property and Purchaser
explicitly took that possibility into account in determining and agreeing to the
Purchase Price.

            (b) Purchaser waives and releases Seller from any present or future
claims arising from or relating to the presence or alleged presence of asbestos
or any hazardous materials or harmful or toxic substances in, on, under or about
the Property, prior to, on or after the date hereof, including without
limitation any claims under or on account of (i) the Comprehensive Environmental
Response, Compensation and Liability Act of 1980, as the same may have been or
may be amended from time to time, and similar state statutes, and any
regulations promulgated thereunder, (ii) any other federal, state or local law,
ordinance, rule or regulation, now or hereafter in effect, that deals with or
otherwise in any manner relates to, environmental matters of any kind, (iii)
this Agreement, or (iv) the common law. The terms and provisions of this
paragraph shall survive Closing hereunder or termination of this Agreement.
Purchaser and its successors and assigns covenant and agree to defend, indemnify
and hold harmless Seller from and against any claims, demands, penalties, fines,
liabilities, settlements, damages, costs or expenses of whatever kind or nature,
relating to any asbestos and hazardous materials or harmful or toxic substances
heretofore or hereafter in, at, about or under the Property.

      1.3. Agreement to Convey. Seller agrees to convey, and Purchaser agrees to
accept, on the Date of Closing: (a) title to the Land and the Improvements by
Massachusetts Statutory quitclaim deed, all in the condition described in
Section 1.2, above, and subject only to the "Permitted Exceptions" described in
Section 3.4 hereof; and (b) title to the Personal Property, by Bill of Sale
(hereinafter defined), without warranty as to the title or the condition of such
personalty. Seller and Purchaser agree to enter into the Sublease at Closing in
the form of Exhibit 1.1A, the Sublease Premises to be in the condition described
in Section 1.2 above and subject to the "Permitted Exceptions" attributable
thereto described in Section 3.4 thereof.

2. Price and Payment.

      2.1. Purchase Price and Payment of Initial Rent. The purchase price for
the Property (other than the Sublease Premises and Adjoining Parcel) (the
"Purchase Price") is Eight Hundred Twenty Million U.S. Dollars
($820,000,000.00). The Purchase Price shall be allocated as follows: The Tower:
$545,000,000.00; The Berkeley Building: $185,000,000.00; The Brown Building:
$90,000,000.00. In addition, Purchaser shall pay the initial rent as and to the
extent required by the Sublease (the "Initial Sublease Rent").

      2.2. Payment. Payment of the Purchase Price and the Initial Sublease Rent,
subject to adjustments for the prorations as provided in Section 6 below, is to
be made by Purchaser wiring immediately available funds to such bank account(s)
as Seller may


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designate, provided, however, the portion of the Purchase Price which
constitutes the Escrow Sum (as defined in Section 11.22) shall be delivered in
escrow to the Title Company as provided in Section 11.22.

      2.3. Closing. Payment of the Purchase Price and the Initial Sublease Rent
and the closing hereunder (the "Closing") will take place pursuant to an escrow
closing simultaneously with the execution of this Agreement (the "Date of
Closing") at Goulston & Storrs, P.C., 400 Atlantic Avenue, Boston, Massachusetts
02110.

3. Inspections and Approvals.

      3.1. Access.

            3.1.1 Purchaser has entered into an Access Agreement with Seller
dated as of December 11, 2002 ("Access Agreement"). Subject to the terms of the
Access Agreement, Seller has allowed Purchaser or Purchaser's agents or
representatives access to the Real Property for purposes of physical and
environmental inspection of the Real Property and review of the Contracts, the
Leases, Seller's books and records relating to the Property (other than any
privileged, proprietary or confidential records), soil reports, environmental
studies and reports, surveys, building and systems plans, income and expense
statements, and other matters necessary in the reasonable discretion of
Purchaser to evaluate and analyze the feasibility of the Property for
Purchaser's intended use thereof. Purchaser, by entering into this Agreement,
confirms and acknowledges to Seller that it has completed all investigations,
reviews and studies it deems appropriate to evaluate the Property and it is
fully satisfied with the scope and content of such investigation.

            3.1.2 Intentionally Omitted.

            3.1.3 Except for Seller's Warranties, Seller makes no
representations or warranties as to the truth, accuracy or completeness of any
materials, data or other information, including without limitation the contents
of the Data Room or Seller's books and records, the Leases, the Contracts, rent
rolls or income and expense statements, supplied to Purchaser in connection with
Purchaser's inspection of the Property. It is the parties' express understanding
and agreement that all such materials were provided by Seller solely for
Purchaser's convenience in making its own examination and as to whether it
wishes to purchase the Property and enter into the Sublease, and, in making such
examination and determination, Purchaser shall rely exclusively on its own
independent investigation and evaluation of the Property and not on any
materials supplied by Seller.

            3.1.4 Intentionally Omitted.

      3.2. Title and Survey. Seller has provided for Purchaser's convenience in
the Data Room for review and printing, commitments by Fidelity National Title
Insurance Company of New York (the "Title Company") to issue an owner's policy
of title insurance (ALTA Form B-1990) insuring the Real Property the Sublease
Premises and the Adjoining Parcel (collectively, the "Title Commitment") and
ALTA surveys (collectively, the "Survey") with respect to the Real Property, the
Sublease Premises and Adjoining Parcel. All matters set


                                       -5-
<PAGE>

forth in or disclosed by the Title Commitment and Survey are deemed approved by
Purchaser as "Permitted Exceptions" as provided in Section 3.4.

      3.3. Contracts. On or before the date hereof, Purchaser has notified
Seller in writing as to which of the Contracts Purchaser elects to assume at
Closing. As used herein, the term "Contracts" shall mean all service,
maintenance, supply or other contracts relating to the operation of the
Property, including those in effect as of the date hereof which are listed on
Exhibit 3.3 attached hereto. At Closing Seller shall provide a notice of
termination to the vendors whose Contract(s) Purchaser has not agreed to assume;
provided however if any such non-assumed Contract does not permit Seller to
terminate same without the same constituting a breach thereof or requires that
Seller pay a fee or penalty to terminate same prior to Closing, Purchaser shall
be required at Closing to assume all obligations thereunder until the effective
date of the termination and to assume the obligation to pay, or to reimburse
Seller for the payment of, the termination fee or penalty.

      3.4. Permitted Exceptions. Purchaser shall be deemed to have approved and
to have agreed to purchase the Real Property and enter into the Sublease subject
only to the following:

            3.4.1 All defects in or to title to the Property or other matters
affecting or relating to the title to, or the survey of, the Property that are
shown on the Survey and Title Commitment and any matter first arising after the
date of the applicable Title Commitment;

            3.4.2 All Contracts and Leases;

            3.4.3 the lien of real and personal property taxes and assessments
which are not yet due and payable;

            3.4.4 rights of parties in possession under the Leases;

            3.4.5 discrepancies, conflicts in boundary lines, shortages in area,
encroachments, and any state of facts which are shown on the Survey regardless
of whether the same are shown by the public records;

            3.4.6 easements or claims of easements not shown by the public
records to the extent shown on the Survey or listed in the applicable Title
Commitment;

            3.4.7 any service, installation, connection, maintenance or
construction charges due after Closing, and, subject to the proration provisions
hereof, charges for sewer, water, electricity, telephone, cable television or
gas;

            3.4.8 rights of vendors and holders of security interests on
personal property installed upon the Property by the tenants under the Leases
and rights of tenants to remove trade fixtures at the expiration of the term of
the Leases in accordance with the terms of their respective Leases;


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            3.4.9 the leases between an affiliate of Seller as tenant and John
Hancock Life Insurance Company as landlord attached hereto as Exhibit 3.4.9
(collectively, the "Affiliate Lease");

            3.4.10 the Naming Agreement;

            3.4.11 Easements and restrictions set forth in the Deed (hereinafter
defined);

            3.4.12 Easement and Facilities Agreement;

            3.4.13 Obligations set forth in the Easement Agreement dated
November 14, 1969 between John Hancock Mutual Life Insurance Company (n/k/a John
Hancock Life Insurance Company) and Boston Young Women's Christian Association,
recorded with Suffolk County Registry of Deeds Book 8333, Page 169 and filed
with the Suffolk County Registry District of the Land Court as Document No.
296543;

            3.4.14 Easements and restrictions set forth in the Easement
Agreement; and

            3.4.15 The Master Lease (hereinafter defined)

All of the foregoing are referred to herein collectively as the "Permitted
Exceptions."

      3.5. Intentionally Omitted.

      3.6. Confidentiality. Unless Seller specifically and expressly otherwise
agrees in writing, Purchaser agrees that it is and remains subject to that
certain Confidentiality Agreement, dated November 26, 2002, between John Hancock
Financial Services, Inc. and Beacon Capital Partners ("Confidentiality
Agreement"). All obligations of Purchaser under this Section 3.6 and the
Confidentiality Agreement shall be referred to as the "Confidentiality
Obligations". Further, Purchaser agrees not to disclose the terms of this
Agreement without the express written consent of Seller. Purchaser shall
indemnify Seller against all costs, claims and damages, including attorneys'
fees, suffered or sustained as the result of Purchaser's breach of the
Confidentiality Obligations. Notwithstanding any other term of this Agreement,
the provisions of this Section 3.6 shall survive Closing or the termination of
this Agreement. Notwithstanding anything to the contrary contained herein or in
the Confidentiality Agreement, Seller acknowledges that Purchaser shall have the
right to disclose the terms of this Agreement and the matters which are the
subject of the Confidentiality Agreement to direct and indirect current and
prospective investors in Purchaser and the Property and lenders to Purchaser and
to current and prospective affiliates of the owners of Purchaser.
Notwithstanding the above, confidentiality is not required as to, and the
parties (and their employees, representatives, and agents) are permitted to
disclose, any information which such parties' counsel advises is necessary to
satisfy the presumption of Treasury Regulations ss.1.6011-4T(b)(3)(iv);
provided, however, that no names, addresses, locations, dollar amounts, or any
other specific factual aspects of the transactions contemplated by this
agreement or any other confidential information contained in this agreement
shall be disclosed unless, and even then only to the extent, any such
information needs to be disclosed as part of the disclosure of the structure and
tax aspects of the


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transactions contemplated by this agreement in order for such disclosure to
satisfy the presumption of Treasury Regulations ss.1.6011-4T(b)(3)(iv). No party
hereto shall be liable to any other party hereto for any disclosure made upon
the advice of counsel and in the good faith belief that such disclosure was
necessary or permitted under the immediately preceding sentence.

4. Prior to Closing.

            Until Closing, Seller or Seller's agents shall:

      4.1. Intentionally Omitted.

      4.2. Intentionally Omitted.

      4.3. Intentionally Omitted.

      4.4. New Leases. Except with respect to those obligations set forth on
Exhibit 4.4, which obligations Seller shall either fulfill prior to Closing or
provide Purchaser a credit with the value of the unfulfilled portion thereof,
Purchaser shall: (a) pay, and/or reimburse Seller at Closing for the paid
portion of all tenant inducements, concessions, construction and improvement
obligations, and brokerage commissions due with respect to any existing Lease or
any expansion, extension or renewal of an existing Lease, and (b) assume all of
Seller's obligations as landlord thereunder with respect to the payment of
tenant improvements and brokerage commissions due after Closing.

      4.5. Capital Work. Seller is in the process of completing certain capital
repairs, replacements and improvements to the Real Property as described in
Exhibit 4.5. If such work is not completed by the Closing, Seller shall credit
Purchaser with all amounts remaining, as of Closing, to be paid under any and
all contracts for such work (including change orders approved as of Closing) and
Seller shall assign to Purchaser and Purchaser shall assume all contracts and
remaining obligations with respect thereto. Purchaser hereby agrees with Seller
that Purchaser, at its cost, shall assume all such contracts in connection with
the Closing in the Assignment and Assumption of Contracts, Warranties and
Guarantees attached to this Agreement as Exhibit 9.2.5 (the "Assignment and
Assumption of Contracts") and promptly complete after Closing the remaining work
in accordance with the scope of work and plans therefor in effect at Closing.
The amount being credited to Purchaser hereunder includes a construction
contingency as set forth on Exhibit 4.5. The unused portion of such contingency
shall be repaid to Seller promptly after completion of and final payment for
each respective capital project. Purchaser shall provide Seller with detailed
back-up reasonably requested by Seller which establishes the utilization of any
contingency. In addition, Seller reserves the right to construct, at its
expense, security desks in the building lobbies based upon plans submitted by
Seller to Purchaser for Purchaser's consent, which consent shall not be
unreasonably withheld or delayed. The provisions of this paragraph shall survive
Closing.

      4.6. Tenant Estoppel Certificates. Seller has prepared and delivered
estoppel certificates in the form attached to any Lease or, if none is attached,
in the form of Exhibit


                                       -8-
<PAGE>

4.6 for each tenant under a Lease (but excluding any licenses, parking
agreements and antennae leases or agreements) (the "Tenant Estoppel
Certificates"). Other than Seller's obligation to deliver a Tenant Estoppel
Certificate with respect to the Affiliate Lease, the failure of any tenant to
return a Tenant Estoppel Certificate, or the submission by a tenant of a
modified Tenant Estoppel Certificate, shall not be deemed a default by Seller
hereunder. The obligations of Purchaser hereunder, however, shall be conditioned
upon the receipt by Purchaser of Tenant Estoppel Certificates substantially in
the form of Exhibit 4.6, or, if another form is specified in a particular Lease,
the form set forth in such Lease, from tenants, including Seller under the
Affiliate Lease, who occupy an aggregate of seventy-five percent (75%) of the
leased premises at the Property, including without limitation the following
tenants: John Hancock Financial Services, Inc., Wachovia Securities, Inc.,
Deloitte & Touche USA LLP, Investors Bank & Trust Company, J&H Marsh & McLennan,
Inc., Hill, Holiday, Connors & Cosmopulos, Inc., Ernst & Young U.S. LLP and
Mercer Management Consulting, Inc. ("Major Tenants"). In the event the required
number of Tenant Estoppel Certificates substantially in the form submitted are
not received, Seller shall have the right, but not the obligation, to substitute
a Seller Estoppel Certificate in the form of Exhibit 4.6-1 attached hereto for
any of the tenants who are not Major Tenants and who do not submit a Tenant
Estoppel Certificate. Such Seller Estoppel Certificate shall be of no further
force or effect as of the date upon which there is delivered to Purchaser a
Tenant Estoppel Certificate substantially in the form submitted from the tenant
in respect of which such Seller Estoppel Certificate was given.

      4.7. Subordination, Non-disturbance and Attornment Agreements. Seller (i)
shall reasonably cooperate with Purchaser's attempts to obtain subordination
and/or non-disturbance and attornment agreements ("SNDAs") from any of the
tenants under any of the Leases to the extent requested by Purchaser's lender,
and (ii) shall cause any affiliate of Seller which is party to the Affiliate
Lease to execute and deliver such SNDAs as may be required under the Affiliate
Lease.

5. Representations and Warranties.

      5.1. By Seller. Seller represents and warrants to Purchaser that as of the
date hereof the following representations and warranties are true in all
material respects:

            5.1.1 Seller is a corporation duly organized and validly existing
under the laws of the Commonwealth of Massachusetts, is authorized to do
business in the Commonwealth of Massachusetts, and has the full power and
authority to execute and deliver this Agreement and all other documents now or
hereafter to be executed and delivered by it pursuant to this Agreement (the
"Seller's Documents"). Subject to Section 5.8, this Agreement constitutes, and
the Seller's Documents will each constitute, the legal, valid and binding
obligations of Seller, enforceable in accordance with their respective terms,
subject to bankruptcy, reorganization and other similar laws affecting the
enforcement of creditors' rights generally and except as may be limited by
general equitable principles.

            5.1.2 Seller has the power to acquire, own, and dispose of the
Property and to engage in the transactions contemplated in this Agreement.


                                      -9-
<PAGE>

            5.1.3 Seller is in good standing under the laws of the Commonwealth
of Massachusetts.

            5.1.4 The execution and delivery of this Agreement and the Seller's
Documents by Seller do not and will not result in a breach of, violate any term
or provision of, or constitute a default or require any consent under, any
articles of incorporation, bylaws, partnership agreement, indenture, deed to
secure debt, deed of trust, mortgage, or, subject to Section 5.8, lease or other
document by which Seller is bound. Subject to Section 5.8, the execution and
delivery of this Agreement, the Seller's Documents and the consummation of the
transactions contemplated hereby and thereby do not and will not require any
consent by any third party that has not been obtained prior to the date of this
Agreement.

            5.1.5 To Seller's Knowledge, Seller has not entered into any
Contracts, Leases or other agreements affecting the Property which will be
binding upon Purchaser after the Closing other than (i) the Contracts listed in
Exhibit 3.3 attached hereto, (ii) the Leases listed in Exhibit 1.1.8 attached
hereto, and (iii) the Permitted Exceptions. To Seller's Knowledge, all of the
Contracts and Leases are in full force and effect in accordance with their
respective terms and except as set forth on Exhibits 3.3 and 1.1.8 respectively
there have been no amendments, modifications or supplements to any of the
Contracts or Leases. True, correct and complete copies of all of the Leases and
the Contracts have heretofore been made available by Seller to Purchaser.

            5.1.6 To Seller's Knowledge, except for defaults cured on or before
the date hereof, Seller has not received or sent any written notice of default
under the terms of any of the Contracts or Leases except as listed in Exhibit
5.1.6-1 attached hereto. To Seller's Knowledge, Exhibit 5.1.6-2 sets forth a
true and complete list of all tenants under any of the Leases who are delinquent
in the payment of any rent or additional rent payable under such applicable
Lease for a period of more than thirty (30) days and the amount of each such
delinquency.

            5.1.7 To Seller's Knowledge, Exhibit 1.1.8 is a true and complete
list of the Leases. To Seller's Knowledge the only tenants of the Property are
the tenants listed in Exhibit 1.1.8 attached hereto and incorporated herein by
this reference; provided, however, that the foregoing is not intended (and shall
not be construed) as a representation by Seller of the parties that are in
actual possession of any portion of the Property since there may be subtenants,
licensees or assignees that are in possession of portions of the Property of
which Seller may not be aware.

            5.1.8 To Seller's Knowledge, Exhibit 1.1.8 sets forth a true and
complete list of (x) all Security Deposits (whether in the form of cash or
letters of credit) made by tenants under the Leases and (y) deposits from
parties under any booking contracts with respect to any auditorium or reception
space located in the Real Property or the Sublease Premises.

            5.1.9 Subject to the qualifications set forth in Section 5.8, (i) to
Seller's Knowledge, the Air Rights Lease is in full force and effect in
accordance with its terms; (ii)


                                      -10-
<PAGE>

there are no amendments, modifications or supplements to the Air Rights Lease,
and (iii) to Seller's Knowledge, there is no default by any party to the Air
Rights Lease.

            5.1.10 Except for those agreements listed on Exhibit 5.1.10, to
Seller's Knowledge, Seller has not entered into any brokerage agreements with
respect to the leasing of portions of the Real Property or the Sublease Premises
or which will be binding on Purchaser after the Closing. Except as otherwise set
forth on Exhibit 4.4, to Seller's Knowledge there are no tenant inducements,
concessions, construction and improvement obligations, or brokerage commissions
due with respect to any existing Lease or any expansion, extension or renewal of
an existing Lease.

            5.1.11 To Seller's Knowledge, Exhibit 5.1.11 is a true and complete
list of all equipment leases for personalty or equipment used by Seller in the
operation or maintenance of the Property to which Seller is a party and which
are currently in effect (the "Equipment Leases"). Except as set forth on Exhibit
5.1.11, to Seller's Knowledge, (i) Seller has not sent or received written
notice of any material default under the terms of any of the Equipment Leases
which default remains uncured and (ii) and except as set forth in Exhibit 5.1.11
there are no amendments, modifications or supplements to any of the Equipment
Leases.

            5.1.12 Except as set forth on Exhibit 5.1.12, to Seller's Knowledge,
there are no actions, suits, arbitrations, claims or proceedings at law or in
equity affecting the Property or Seller's ability to perform under this
Agreement and Seller has not received any written notices of any such threatened
or contemplated actions, suits, arbitrations, claims or proceedings which claims
would not be covered by insurance (subject to deductibles).

            5.1.13 None of Seller's employees engaged in the operation and
maintenance of the Property are subject to any collective bargaining agreements
or union agreements which will be binding on Purchaser after the Closing.

            5.1.14 To Seller's Knowledge, the Property is in material compliance
with applicable Environmental Laws. For purposes hereof, "Environmental Laws"
means the Comprehensive Environmental Response Compensation and Liability Act of
1980, the Resource Conservation an Recovery Act of 1976, each as amended,
together with all other applicable laws (including rules, regulations, codes,
plans, contaminant levels, clean-up levels, injunctions, judgments, orders,
decrees, rulings, and charges thereunder) of federal, state, local, and foreign
governments (and all agencies thereof) concerning pollution or protection of the
environment, including laws relating to emissions, discharges, releases, or
threatened releases of pollutants, contaminants, or chemical, industrial,
hazardous, or toxic or other materials or wastes into ambient air, surface
water, ground water, or lands or otherwise relating to the manufacture,
processing, distribution, use, treatment, storage, disposal, transport, or
handling of pollutants, contaminants, or chemical, industrial, hazardous, or
toxic or other materials or wastes; all to the extent applicable to the Property
or any operations conducted thereat.

            5.1.15 To Seller's Knowledge, Seller has not received any written
notice from any governmental official or agency that the Property is not in
material compliance with


                                      -11-
<PAGE>

applicable laws, codes and regulations, except for such failures to comply, if
any, which have been remedied.

      5.2. By Purchaser. Purchaser represents and warrants to Seller that as of
the date hereof the following representations and warranties are true in all
material respects:

            5.2.1 Purchaser is a limited liability company duly organized,
validly existing and in good standing under the laws of the State of Delaware,
and prior to Closing authorized to do business in the Commonwealth of
Massachusetts, has duly authorized the execution and performance of this
Agreement, and such execution and performance by Purchaser of this Agreement
will not violate any material term of its certificate of incorporation or
by-laws. All necessary approvals for this transaction have been given and no
additional action by any board, committee or individual within Purchaser's
organization or any entity affiliated with Purchaser is required to consummate
this transaction. Purchaser is acting as principal in this transaction with
authority to close this transaction. Neither Purchaser nor any affiliate of or
principal in Purchaser is other than a citizen of, or partnership, corporation
or other form of legal person domesticated in, the United States. No petition in
bankruptcy (voluntary or otherwise), assignment for the benefit of creditors, or
petition seeking reorganization or arrangement or other action under Federal or
State bankruptcy law is pending against or contemplated by Purchaser.

            5.2.2 Purchaser (a) has inspected the Property fully and completely
at its expense and has ascertained to its satisfaction the extent to which the
Property complies with applicable zoning, building, environmental, health and
safety and all other laws, codes and regulations, and (b) has reviewed the
Leases, the Contracts, the Survey, the Title Commitment, books and records,
expenses and other matters relating to the Property, including, without
limitation, the Data Room, and, based upon its own investigations, inspections,
tests and studies, and Seller's Warranties shall have determined whether to
purchase the Property and to assume Seller's obligations under the Leases,
Contracts and otherwise with respect to the Property.

            5.2.3 Purchaser will not use "plan assets" as defined in the
Employee Retirement Income Security Act of 1974, as amended ("ERISA") and
covered under Title 1, Part 4 of ERISA or Section 4975 of the Internal Revenue
Code of 1986, as amended, in the performance or discharge of its obligations
hereunder, including the acquisition of the Property. Purchaser shall not assign
its interest hereunder to any person or entity which does not expressly make
this covenant and warranty for the benefit of Seller.

            5.2.4 Purchaser's examination of the Property and the books and
records, Leases and other matters related to the Property to date have not
revealed any matters which would affect the Purchase Price or Purchaser's
willingness to proceed with the transaction.

      5.3. Broker. Each of Seller and Purchaser represents to the other that it
has had no dealings, negotiations, or consultations with any broker,
representative, employee, agent or other intermediary in connection with the
sale of the Property and the entering into of the Sublease, except that (i)
Seller has retained the services of Morgan Stanley Realty


                                      -12-
<PAGE>

Incorporated (the "Broker"), and the payment of any fee or commission to the
Broker shall be subject to the terms and conditions of a separate written
agreement between Seller and the Broker and (ii) Purchaser has retained the
services of Lehman Brothers Holdings Inc. ("Lehman") as an adviser in the
transaction and the payment of any fee or commission to Lehman shall be paid in
full by Purchaser subject to the terms and conditions of a separate written
agreement between Purchaser and Lehman but in no event shall Seller have any
liability to Lehman. Seller and Purchaser agree that each will indemnify, defend
and hold the other free and harmless from the claims of any other broker(s),
representative(s), employee(s), agent(s) or other intermediary(ies) claiming to
have represented Seller or Purchaser, respectively, or otherwise to be entitled
to compensation in connection with this Agreement or in connection with the sale
of the Property.

      5.4. Seller's Knowledge. For purposes of this Agreement, the term
"Seller's Knowledge") or words of similar import, shall refer only to the actual
knowledge of Paul Crowley, John Heavey and John Durnan (who are responsible for
oversight of the operations, leasing and security at the Property)(collectively,
the "Real Estate Operations Individuals"), and shall not be construed to refer
to the knowledge of any other beneficial owner, officer, director, employee,
shareholder or agent of Seller, nor shall such term impose any duty to
investigate the matters to which such knowledge, or absence thereof, pertain.
There shall be no personal liability on the part of the Real Estate Operations
Individuals arising out of any representations or warranties made herein or
otherwise.

      5.5. Effect of Tenant Estoppel Certificate. To the extent a Tenant
Estoppel Certificate is provided to Purchaser which sets forth information with
respect to any item as to which Seller has made a representation or warranty,
then Seller's representation and warranty with respect to such information will
thereafter be null and void and of no further force and effect and Purchaser
shall rely on the information in the Tenant Estoppel Certificate.

      5.6. No Representation as to Leases. Seller does not represent or warrant
that any particular Lease or Leases will be in force or effect on the Date of
Closing or that the tenants will have performed their obligations thereunder
other than the Affiliate Lease and the Master Lease.

      5.7. Seller's Warranties Deemed Modified. To the extent that Purchaser
knows or is deemed to know that Seller's representations and warranties are
inaccurate, untrue or incorrect in any way, such representations and warranties
shall be deemed modified to reflect Purchaser's knowledge or deemed knowledge,
as the case may be. For purposes of this Agreement, Purchaser shall be deemed to
know a representation or warranty of Seller is untrue or incorrect, if any
estoppel certificate delivered in connection with this Agreement, any exhibits
to this Agreement any document in the Data Room to which Purchaser has been
provided access, or any test, report, analysis or study undertaken for Purchaser
contains information which is inconsistent with such Seller's representation or
warranty.

      5.8. Limitation of Representations. Any representation or warranty made by
Seller under Section 5.1 above, including particularly but without limitation,
Section 5.1.1 and


                                      -13-
<PAGE>

5.1.4, shall not be deemed to include any representation or warranty with
respect to the effect of any of the Seller's Documents, including without
limitation the Sublease, or the Air Rights Lease or whether the entering into of
any Seller's Documents requires any consents or creates any defaults under the
Air Rights Lease. No covenant or undertaking of Seller under any Seller
Documents to maintain the Air Rights Lease in full force and effect or without
default, or any covenants or words of similar import shall apply to the effect
of this transaction on the Air Rights Lease. Purchaser hereby acknowledges that
it is entering into this transaction with full understanding and knowledge of
the terms of the Air Rights Lease. Neither Seller nor Purchaser shall have any
liability one to the other with respect to any claim that this transaction
caused a violation of the Air Rights Lease.

      5.9. Survival; Limitation on Seller's Liability. Seller's representations
and warranties set forth in this Agreement, including without limitation those
representations and warranties set forth in Section 5.1, or in any of the
documents executed by Seller at Closing (other than the Easement Agreement, the
Easement and Facilities Agreement, the Sublease, and any of the documents
executed in connection with the provisions of Section 11.22 below), including,
without limitation, indemnification obligations set forth in such other
documents ("Seller's Warranties") shall survive the Closing until December 31,
2003, and not be merged therein days and Seller shall be liable to Purchaser
hereunder for a breach of a Seller's Warranties with respect to which a claim is
made by Purchaser against Seller on or before the first anniversary of the Date
of Closing (the "Survival Date") and an action is commenced by Purchaser against
Seller with respect to such claim within ninety (90) days after such claim is
made. Anything in this Agreement to the contrary notwithstanding, the maximum
aggregate liability of Seller for breaches of Seller's Warranties shall not
exceed the lesser of Purchaser's actual damages and one percent (1%) of the
Purchase Price in the aggregate (the "Damage Cap"), nor shall any claim be made
unless the aggregate claim of damage for all such matters, taken as a whole, is
greater than two hundred fifty thousand dollars ($250,000). Notwithstanding the
foregoing, however, Purchaser hereby expressly waives, relinquishes and releases
any right or remedy available to it at law or in equity, under this Agreement or
otherwise to make a claim against Seller for damages that Purchaser may incur,
or to rescind this Agreement and the transaction, as the result of any of
Seller's Warranties being untrue, inaccurate or incorrect if Purchaser knew or
is deemed to know at the time of the Closing that such representation or
warranty was untrue, inaccurate or incorrect.

6. Costs and Prorations.

      6.1. Purchaser's Costs. Purchaser will pay the following costs of closing
this transaction:

            6.1.1 Any expense(s) incurred by Purchaser or its representative(s)
in inspecting or evaluating the Property or closing this transaction, including,
without limitation, the fees and disbursements of its counsel, inspecting
architect and engineer and consultants, if any;

            6.1.2 All recording fees;


                                      -14-
<PAGE>

            6.1.3 Escrow fees, if any;

            6.1.4 The cost of an ALTA owner's title insurance policy, and any
and all special endorsements, co-insurance and reinsurance issued to Purchaser
in connection with this transaction, whether pursuant to the Title Commitment or
otherwise; and

            6.1.5 The cost of any updates or modifications to the Survey;

      6.2. Seller's Costs. Seller will pay the following costs of closing this
transaction:

            6.2.1 The fees and disbursements of Seller's counsel;

            6.2.2 The documentary transfer tax; and

            6.2.3 The Broker's fee to the extent any such fee is payable
pursuant to Seller's separate written agreement with the Broker referred to in
Section 5.3, above.

      6.3. Other Closing Costs. Any closing costs not enumerated above shall be
paid in accordance with the custom and practice in Boston, Massachusetts for
transactions of this type.

      6.4. Prorations. (a)(i) All normal and customarily proratable items,
including without limitation, real estate and personal property taxes and
assessments, utility bills (except as hereinafter provided), collected rents and
other income, and Contract payments (under Contracts assumed by Purchaser),
shall be prorated as of the Date of Closing, Seller being charged and credited
for all of the same relating to the period up to the Date of Closing and
Purchaser being charged and credited for all of the same relating to the period
on and after the Date of Closing. If the amount of any such item is not known on
the Date of Closing, such item shall be apportioned on the basis of the
comparable period of the prior year with a reapportionment within ninety (90)
days of the Date of Closing or as soon thereafter as the amount of the item is
actually determined but in no event later than March 31, 2004. No proration
shall be made in relation to delinquent or other uncollected rents, common area
expense charges or tax payments, (collectively, "Uncollected Rents") existing,
if any, as of the Date of Closing. To the extent that interim reimbursements of
real estate taxes and operating expenses are made by tenants under the Leases
and have been collected by Seller prior to the Closing, such payments may be
retained by Seller without duty to account therefor to Purchaser (unless such
reimbursements are prepayments of amounts due and payable and relating to the
period after the Closing in which event such amounts shall be remitted to
Purchaser at Closing).

                        (ii) With respect to tax and operating expense charges
      to tenants for the fiscal period in which the Closing occurs, Purchaser
      shall submit to Seller the end of period calculations of readjustments
      prior to submitting the same to tenant. The calculations shall be subject
      to Seller's approval which shall not be unreasonably withheld or delayed.
      If such readjustment reflects monies owed to tenants, Seller shall pay to
      Purchaser for repayment to tenants its prorata share of such amounts. If
      such readjustment reflects monies owed by tenants, Purchaser shall


                                      -15-
<PAGE>

      pay to Seller its prorata share when and as collected from such tenants.
      If, however, such readjustment cannot be made prior to March 31, 2004,
      there shall be no readjustment or "true up" between Seller and Purchaser
      whether or not a readjustment reflects monies owed by or to tenants for
      such fiscal period.

                        (iii) With respect to percentage rent payable under the
      Leases for any lease year ending prior to Closing, any and all percentage
      rent shall belong to Seller. To the extent that any such percentage rent
      is received by Purchaser, Purchaser shall promptly pay over the same to
      Seller. With respect to any lease year during which the Closing shall take
      place, Seller shall be entitled to that portion thereof represented by
      multiplying such percentage rent by a fraction, the numerator of which is
      the number of days of such lease year occurring prior to Closing and the
      denominator of which is 365. Purchaser shall be entitled to the balance
      thereof. Purchaser agrees to use reasonable efforts to collect such
      percentage rent (with no obligation, however, to incur any additional
      out-of-pocket costs with respect thereto) and promptly after receipt
      thereof by Purchaser, the same shall be allocated as aforesaid and paid to
      Seller.

                        (iv) With respect to operating expenses, taxes and
      utility charges payable by tenants under the Leases, to the extent that
      Seller has received as of the Closing payments allocable to a period
      subsequent to the Closing, same shall be properly prorated with an
      adjustment in favor of Purchaser. With respect to any payments received by
      Purchaser after the Closing allocable to a period prior to Closing,
      Purchaser shall promptly pay the same to Seller.

                        (v) Purchaser shall pay Uncollected Rent of Seller as
      and when collected by Purchaser, it being agreed that any rents collected
      by Purchaser shall first be applied to rents due in the month of Closing,
      then to rents currently due after Closing and the balance to Uncollected
      Rents. Purchaser agrees to bill tenants of the Property for all
      Uncollected Rents and to take any additional reasonable actions requested
      by Seller to collect Uncollected Rents provided that Purchaser shall not
      be obligated to incur any material out-of-pocket third party expense in
      connection with such actions and Purchaser shall not be obligated to take
      any action to terminate a tenancy. Seller reserves the right to bring suit
      against tenants of the Property to collect for Uncollected Rent (and other
      charges due to Seller for the period prior to the Closing) but Seller may
      not, subsequent to the date hereof, bring suit for possession of the
      premises occupied by such tenants.

                        (vi) Final readings and final billings for utilities
      will be made as soon after the Date of Closing as is reasonably possible.
      A proration shall be made based upon the parties' reasonable good faith
      estimate and a readjustment made within thirty (30) days after Closing or
      such later date as shall be necessary so that such readjustment may be
      based upon actual bills for such utilities. No proration will be made in
      relation to insurance premiums and the insurance policies will not be
      assigned to Purchaser, except to the extent insurance premiums are
      included in common area expenses, in which event they shall be prorated as
      provided above.


                                      -16-
<PAGE>

      Seller shall be entitled to receive a return of all deposits presently in
      effect with the utility providers, and Purchaser shall be obligated to
      make its own arrangements for deposits with the utility providers.

                        (vii) Purchaser shall receive a credit for all security
      deposits from tenants then held by Seller (the "Security Deposits") which
      are in cash and in such event Purchaser shall assume all of Seller's
      obligations to repay such Security Deposits to tenants. With respect to
      any Security Deposits which are letters of credit, Seller shall, if the
      same are assignable, deliver to Purchaser at the Closing such letters of
      credit and shall execute and deliver such other instruments as the issuers
      of such letters of credit shall require to assign such letters of credit
      to Purchaser. Seller shall cooperate with Purchaser to change the name of
      the beneficiary under such letters of credit so long as Seller does not
      incur any additional cost or expense in connection therewith.

                        (viii) Charges and revenue(s) under any parking
      agreements shall be apportioned based on revenues for the month preceding
      Closing and shall be re-adjusted as promptly as possible after the Closing
      to accurately reflect the daily charges and revenues paid for the month of
      March.

                        (ix) Charges and revenue(s) under any of the license
      agreements listed as "antennae agreements" on Schedule 1.1.8 shall be
      apportioned in accordance with Sections 6.1(a)(i) through (v).

                        (x) Rent, additional rent and other charges with respect
      to the Air Rights Lease shall be apportioned in a customary and normal
      manner.

                        (xi) Revenues with respect to the Cafeteria Agreement
      shall be apportioned based on revenues for the month preceding Closing and
      all operating expenses and other costs payable by Seller under the Private
      Center Management Agreement NO DP 272000 dated February 11, 2000, between
      Seller and Fitcorp HealthCare Centers, Inc. as amended and under the
      Cafeteria Agreement, as applicable, shall be apportioned based on the
      expenses for the month preceding Closing so that Seller is allocated that
      portion of such operating expenses and other costs attributable to the
      period preceding the Date of Closing and Purchaser is allocated the
      balance and shall be re-adjusted as promptly as possible after the Closing
      to accurately reflect the expenses and revenues paid in March.

                        (xii) Purchaser shall receive a credit with respect to
      all reimbursements owed to and deposits from parties under any booking
      contracts with respect to any auditorium space located in the Real
      Property and parties to any Contracts which are then held by Seller and in
      such event Purchaser shall assume all of Seller's obligations to repay
      such reimbursements and deposits to the applicable parties under such
      contracts.

                        (xiii) The provisions of this Section 6.4 shall survive
      the Closing until March 31, 2004, and in the event of any error in
      performing the


                                      -17-
<PAGE>

      prorations contemplated by this Agreement or if information becomes
      available subsequent to the Closing indicating that the prorations
      performed at Closing were not accurate the parties hereto shall be
      obligated promptly to re-prorate the closing adjustments to correct such
      errors and to reflect such new information.

                  (b) Seller shall prepare a detailed statement setting forth
all closing adjustments and shall deliver same to Purchaser (together with all
supporting data) not less than five (5) business days prior to Closing.

                  (c) With respect to any Contracts which include property of
Seller in addition to the Property, Seller shall endeavor to cause the contracts
to be severed between the Property and Seller's other property in a manner which
does not adversely affect the terms of the portion of the applicable contract
that remains in effect at the Property. Until such time, Seller and Purchaser
shall allocate the costs thereunder in a fair and equitable manner.

      6.5. Purpose and Intent. Except as expressly provided herein, the purpose
and intent as to the provisions of prorations and apportionments set forth in
this Section 6 and elsewhere in this Agreement is that Seller shall bear all
expenses of ownership and operation of the Property and shall receive all income
therefrom accruing through midnight at the end of the day preceding the Closing
and Purchaser shall bear all such expenses and receive all such income accruing
thereafter; provided, however, that if Seller does not receive the Purchase
Price in immediately-available funds by 12:00 p.m. E.S.T. on the Date of
Closing, all adjustments and prorations shall be made as of midnight on the next
business day immediately following the Date of Closing.

7. Damage, Destruction or Condemnation.

      7.1. Intentionally Omitted.

      7.2. Intentionally Omitted.

      7.3. Intentionally Omitted.

8. Notices.

                  Any notice, request, demand, consent, approval and other
communications under this Agreement shall be in writing, and shall be deemed
duly given or made at the time and on the date when received by facsimile
(provided that the sender of such communication shall orally confirm receipt
thereof by the appropriate parties and send a copy of such communication to the
appropriate parties within one (1) business day of such facsimile) or when
personally delivered as shown on receipt therefor (which shall include delivery
by a nationally recognized overnight delivery service) or three (3) business
days after being mailed by prepaid registered or certified mail, return receipt
requested, to the address for each party set forth below. Any party, by written
notice to the other in the manner herein provided, may designate an address
different from that set forth below.


                                      -18-
<PAGE>

            If to Seller:

            John Hancock Life Insurance Company
            380 Stuart Street S-8
            Boston, Massachusetts 02117
            Attn: Paul M. Crowley, Vice President
            Phone: (617) 572-0037
            Fax: (617) 572-1432

            With a copy to:

            John Hancock Life Insurance Company
            200 Clarendon Street
            30th Floor
            Boston, MA 02117
            Attn: Michael M. Epstein, Vice President and Counsel
            Phone: (617) 572-9247
            Fax: (617) 572-9268

            With a copy to:

            Goulston & Storrs, P.C.
            400 Atlantic Avenue
            Boston, MA 02110-3333
            Attn: David M. Abromowitz
            Phone: 617-574-4016
            Fax: 617-574-7563

            If to Purchaser:

            Beacon Capital Partners, LLC
            One Federal Street, 26th Floor
            Boston, Massachusetts 02110
            Attn.: General Counsel
            Fax: (617) 457-0499
            Phone: (617) 457-0459

            With a copy to:

            Willkie Farr & Gallagher
            787 7th Avenue
            New York, New York 10019
            Attn.: Eugene A. Pinover, Esq.
            Fax: (212) 728-8111
            Phone: (212) 728-8000


                                      -19-
<PAGE>

            If to Title Company:

            Fidelity National Title Insurance Company
            133 Federal Street
            Boston, MA  02110
            Attn:  Kevin Creedon
            Phone: (617) 350-8828
            Fax: (617) 350-8826

9. Closing and Escrow.

      9.1. Escrow Instructions. Seller and Purchaser agree to execute such
additional and supplementary escrow instructions to enable the Title Company to
comply with the terms of this Agreement, provided, however that in the event of
any conflict between the provisions of this Agreement and any supplementary
escrow instructions, the terms of this Agreement shall prevail.

      9.2. Seller's Deliveries. Seller shall deliver either at the Closing or by
making available at the Property, as appropriate, the following original
documents, each executed and, if required, acknowledged:

            9.2.1 Massachusetts statutory quitclaim deeds to the Property (other
than the Sublease Premises, the Garage and Adjoining Parcel), in the form
attached hereto as Exhibit 9.2.1 (the "Deed"), subject only to the Permitted
Exceptions.

            9.2.2 The Sublease.

            9.2.3 Bills of sale in the form attached hereto as Exhibit 9.2.3
(the "Bill of Sale"), conveying the Personal Property to Purchaser.

            9.2.4 (i) The Leases described in Section 1.1.8 which are still in
effect as of Closing; (ii) a current listing of any Security Deposits and
prepaid rents held by Seller with respect to the Property; (iii) an assignment
of such Leases, deposits, and prepaid rents by way of an assignment and
assumption agreement in the form attached hereto as Exhibit 9.2.4 (the
"Assignment and Assumption of Leases"); and (iv) originals of those letters of
credit held as Security Deposits, together with forms of transfer or other
instruments required to be executed by Seller to effect the transfer to
Purchaser.

            9.2.5 (i) Copies of all Contracts relating to the Property which
Purchaser has elected to assume or which are not terminated by Seller on or
before the Date of Closing and all booking agreements to which Seller is a
party; and (ii) an assignment of such Contracts and booking agreements to
Purchaser by way of an assignment and assumption agreement, in the form attached
hereto as Exhibit 9.2.5.

            9.2.6 An assignment of all Approvals (to the extent assignable) and
all transferable warranties and guarantees then in effect, if any, with respect
to the


                                      -20-
<PAGE>

Improvements or any repairs or renovations to such Improvements and the Personal
Property being conveyed hereunder, in the form attached hereto as Exhibit 9.2.5.

            9.2.7 An assignment and assumption, in the form attached as Exhibit
9.2.7, of each of the following agreements between the Seller and the City of
Boston, acting through its Public Improvement Commission; (i) Agreement re:
Tunnel, dated September 24, 1970, (ii) License, Maintenance and Indemnification
Agreement re: Sidewalk Improvements, dated July 25, 2002, (iii) License
Agreement re: vault under Stuart Street, dated August 1, 1997, and (iv) License
Agreement re: Stuart Street conduits, dated July 31, 1986.

            9.2.8 That certain master lease between Seller as tenant and
Purchaser as Landlord (the "Master Lease") in the form attached hereto as
Exhibit 9.2.8.

            9.2.9 The Easement Agreement.

            9.2.10 Resolutions reasonably required by the Title Company
evidencing Seller's authority to enter into this transaction and the entering
into of the Affiliate Lease and incumbency certificates.

            9.2.11 An estoppel letter from Seller with respect to the Air Rights
Lease in the form of Exhibit 9.2.11-1 and with respect to the Sublease in the
form of Exhibit 9.2.11-2.

            9.2.12 All books and records with respect to the Property located at
the Property held by or for the account of Seller, including without limitation
plans and specifications, lease applications, technical manuals, originals of
all tenant files and correspondence, licenses and permits currently maintained
by Seller in connection with its ownership of the Property and any similar
materials for the Property to the extent the same have not been previously
delivered to Purchaser and to the extent in Seller's possession and control and,
to the extent originals are not available, copies of the foregoing.

            9.2.13 An affidavit pursuant to the Foreign Investment and Real
Property Tax Act, in the form attached hereto as Exhibit 9.2.13.

            9.2.14 Title insurance affidavits sufficient to allow the Title
Company to remove from Purchaser's owner's title insurance policy or policies
any exception for parties in possession (except for tenants claiming pursuant to
the Leases) and for mechanics liens.

            9.2.15 The Affiliate Lease.

            9.2.16 The Naming Agreement.

            9.2.17 The Easement and Facilities Agreement ("Easement and
Facilities Agreement Assignment").

            9.2.18 An original of a closing statement setting forth the Purchase
Price and the closing adjustments and prorations (the "Closing Statement") in
form reasonably satisfactory to Purchaser and Seller.


                                      -21-
<PAGE>

            9.2.19 Original tenant notification letters (notifying tenants of
the transfer of the Property to Purchaser) for each tenant under a Lease or
other occupant of any portion of the Property, and original notification letters
to all parties to Contracts assigned to Purchaser, each in form reasonably
satisfactory to Purchaser.

            9.2.20 Evidence of payment to the Broker.

            9.2.21 A Designation of Person Responsible for Tax Reporting under
Internal Revenue Code Section 6045 in the form of Exhibit 9.2.21 annexed hereto
designating Seller's attorney as the party responsible for making the returns
required under Internal Revenue Code Section 6045.

            9.2.22 To the extent that any Contracts are to be canceled or
terminated in accordance with the provisions of Section 3.3 above, Seller shall
deliver evidence of notice of such cancellation or termination.

            9.2.23 Evidence satisfactory to the Title Company that all necessary
approvals and/or consents by Seller and any constituent person of Seller
otherwise required under Seller's organizational documents, have been delivered
and such other evidence reasonably satisfactory to the Title Company of Seller's
authority and the authority of the signatory on behalf of Seller to convey the
Property pursuant to this Agreement.

            9.2.24 A subordination non-disturbance and attornment agreement to
Purchaser's lender in the form provided for in the Affiliate Lease.

            9.2.25 A notice to the MTA of the mortgage joined in by Seller with
respect to Seller's sublease interest in the Air Rights Lease in the form
attached hereto as Exhibit 9.2.25.

      9.3. Purchaser's Deliveries. At the Closing, Purchaser shall (i) pay
Seller the Purchase Price and Initial Sublease Rent as required by, and in the
manner described in, Section 2 hereof; (ii) execute any agreements referred to
in Section 9.2 hereof requiring counter-execution by Purchaser (including
without limitation the Sublease, the Master Lease, Naming Agreement and Easement
and Facilities Agreement Assignment); (iii) execute the Closing Statement
referred to in Section 9.2.18; and (iv) execute and deliver such other documents
and instruments as may be reasonably required by the Title Company.

      9.4. Possession. Subject to the Affiliate Lease, the Master Lease and the
Sublease, Purchaser shall be entitled to possession of the Property at the
conclusion of the Closing.

10. Default; Failure of Condition.

      10.1. Intentionally Omitted.

      10.2. Intentionally Omitted.


                                      -22-
<PAGE>

      10.3. Conditions to Purchaser's Obligations. Purchaser's obligations to
close the transaction is conditioned on all of the following, any or all of
which may be expressly waived by Purchaser in writing, at its sole option:

            10.3.1 Representations True. Subject to the provisions of Section
5.7, all representations and warranties made by Seller in this Agreement, as the
same may be modified or deemed modified as provided in Sections 5.7, shall have
been be true and correct in all material respects as of the date of this
Agreement.

            10.3.2 Title Conditions Satisfied. At the time of the Closing, title
to the Property shall be as provided in Sections 3.2 and 3.4 of this Agreement.

            10.3.3 Seller's Deliveries Complete. Seller shall have delivered all
of the documents and other items required pursuant to Section 9.2 and shall have
performed in all material respects all other covenants, undertakings and
obligations to be performed with by Purchaser at or prior to the Closing.

            10.3.4 Estoppel Certificates. Purchaser shall have received the
requisite tenant Estoppel Certificates or Seller Estoppel Certificate provided
for in Section 4.6 above.

            10.4. Conditions to Seller's Obligations. Seller's obligations to
close the transaction is conditioned on all of the following, any and all of
which may be waived by Seller by an express written waive, at its sole option:

            10.4.1 Representations True. All representations and warranties made
by Purchaser in this Agreement shall have been be true and correct in all
material respects as of the date of this Agreement and shall be true in all
material respects as if such representations and warranties were made at and as
of the Date of Closing.

            10.4.2 Deliveries Complete. Purchaser shall have delivered the funds
required hereunder and all of the documents to be executed by Purchaser set
forth in Section 9.3 and shall have performed in all material respects all other
covenants, undertakings and obligations to be performed by Purchaser at or prior
to the Closing.

      10.5. Waiver of Failure of Conditions Precedent. At any time or times on
or before the date specified for the satisfaction of any condition, Seller or
Purchaser may elect in writing to waive the benefit of any such condition set
forth in Section 10.3 and 10.4 respectively. Except as otherwise expressly set
forth in Section 10.2, by closing the transaction, Seller and Purchaser shall be
conclusively deemed to have waived the benefit of any remaining unfulfilled
conditions set forth in Section 10.3 and 10.4 respectively.

11. Miscellaneous.

      11.1. Entire Agreement. This Agreement, together with the Exhibits
attached hereto, all of which are incorporated by reference, is the entire
agreement between the parties with respect to the subject matter hereof, and no
alteration, modification or interpretation hereof shall be binding unless in
writing and signed by both parties.


                                      -23-
<PAGE>

      11.2. Severability. If any provision of this Agreement or application to
any party or circumstances shall be determined by any court of competent
jurisdiction to be invalid and unenforceable to any extent, the remainder of
this Agreement or the application of such provision to such person or
circumstances, other than those as to which it is so determined invalid or
unenforceable, shall not be affected thereby, and each provision hereof shall be
valid and shall be enforced to the fullest extent permitted by law.

      11.3. Applicable Law. This Agreement shall be construed and enforced in
accordance with the law of the Commonwealth of Massachusetts.

      11.4. Assignability. Purchaser may not assign this Agreement without first
obtaining Seller's written consent; provided, however, (x) Purchaser may
designate all of its rights under this Agreement to one or more separate
entities each to take title to the fee interests associated with the Tower, the
Berkeley Building and the Brown Building (the latter two to one single entity),
to take an assignment of Seller's interest in the Easements and to enter into
the Sublease and Master Lease without Seller's prior written consent, in which
event Seller shall, otherwise in accordance with the terms of this Agreement,
convey title with respect to the fee interests associated with each of the
Tower, the Berkeley Building and the Brown Building, assign Seller's interest in
the Easements and enter into the Sublease and Master Lease to such designee as
directed by Purchaser and such designee shall be entitled to exercise any and
all rights of Purchaser which survive Closing which relate to that portion of
the Property that such designee acquires; provided that any such designee or its
owner must have a general partner or managing member which is majority owned and
controlled by Beacon Capital Strategic Partners II, L.P. (directly or
indirectly), and (y) Purchaser, or any permitted designee, may collaterally
assign any and all rights of Purchaser that survive the Closing to a lender
making a loan to Purchaser or such permitted designee, which loan is secured in
whole or in part by the Property. Purchaser shall notify Seller of its intent to
cause title to be transferred to any such permitted designee at least three (3)
business days prior to the Closing Date, and shall deliver to Seller copies of
the documents of assignment and assumption executed in connection therewith as
reasonably approved by Seller. Any assignment in contravention of this provision
shall be void. No assignment or designation shall release the Purchaser herein
named from any obligation or liability under this Agreement.

      11.5. Successors Bound. This Agreement shall be binding upon and inure to
the benefit of Purchaser and Seller and their respective successors and
permitted assigns.

      11.6. No Public Disclosure. All press releases or other dissemination of
information to the media or responses to requests from the media for information
relating to the transaction contemplated herein shall be subject to the prior
written approval of Seller; provided that, following Closing, Seller's approval
shall not be unreasonably withheld or delayed.

      11.7. Captions. The captions in this Agreement are inserted only as a
matter of convenience and for reference and in no way define, limit or describe
the scope of this Agreement or the scope or content of any of its provisions.


                                      -24-
<PAGE>

      11.8. No Partnership. Nothing contained in this Agreement shall be
construed to create a partnership or joint venture between the parties or their
successors in interest.

      11.9. Time of Essence. Time is of the essence in this Agreement.

      11.10. Counterparts. This Agreement may be executed and delivered in any
number of counterparts, each of which so executed and delivered shall be deemed
to be an original and all of which shall constitute one and the same instrument.

      11.11. Recordation. Purchaser and Seller agree not to record this
Agreement or any memorandum hereof.

      11.12. Proper Execution. The submission by Seller to Purchaser of this
Agreement in an unsigned form shall be deemed to be a submission solely for
Purchaser's consideration and not for acceptance and execution. Such submission
shall have no binding force and effect, shall not constitute an option or an
offer, and shall not confer any rights upon Purchaser or impose any obligations
upon Seller irrespective of any reliance thereon, change of position or partial
performance. The submission by Seller of this Agreement for execution by
Purchaser and the actual execution thereof and delivery to Seller by Purchaser
shall similarly have no binding force and effect on Seller unless and until
Seller shall have executed this Agreement and a counterpart hereof executed by
Seller and Purchaser shall have been delivered to Purchaser.

      11.13. Tax Protest. If as a result of any tax protest or otherwise any
refund or reduction of any real property or other tax or assessment relating to
the Property during the period for which, under the terms of this Agreement,
Seller is responsible, Seller shall be entitled to receive or retain such refund
or the benefit of such reduction, less equitable prorated costs of collection.

      11.14. Intentionally omitted.

      11.15. Intentionally omitted.

      11.16. Liability of Seller. It is hereby expressly agreed that any
liability by Seller arising hereunder, for any reason whatsoever, shall be
limited to Seller's interests in and to the Property and any proceeds received
therefrom. It is further hereby expressly agreed that in no event shall any
officer, director, employee, agent or representative of Seller have any personal
liability in connection with this Agreement or the transaction envisioned
herein.

      11.17. Waiver. No waiver of any breach of any agreement or provision
contained herein shall be deemed a waiver of any preceding or succeeding breach
of any other agreement or provision herein contained. No extension of time for
the performance of any obligation or act shall be deemed an extension of time
for the performance of any other obligation or act.

      11.18. Seller's Performance. The acceptance by Purchaser of the Deed, the
Sublease, the Master Lease, the Bill of Sale and other documents delivered to
Purchaser at Closing


                                      -25-
<PAGE>

shall be deemed to be full performance and discharge of every agreement and
obligation of Seller herein contained and expressed, except such as are, by the
express terms hereof, to be performed by Seller after the delivery of said
instrument.

      11.19. Title Company. In performing any of its duties hereunder, the Title
Company shall not incur any liability to anyone for any damages, losses or
expenses, except for those arising out of its willful default, gross negligence
or breach of trust, and the Title Company shall accordingly not incur any such
liability with respect (a) to any action taken or omitted in good faith upon
advice of its counsel, or (b) to any action taken or omitted in reliance upon
any written notice or instruction provided for in this Agreement. Seller and
Purchaser hereby agree to indemnify and hold harmless the Title Company from and
against any and all losses, claims, damages, liabilities and expenses, including
reasonable attorneys' fees, which may be incurred by the Title Company in
connection with its acceptance or performance of its duties hereunder, including
any litigation arising from this Agreement or involving the subject matter
hereof, except in the case of Title Company's willful default, gross negligence
or breach of trust. In the event of a dispute between Seller and Purchaser
sufficient in the discretion of the Title Company to justify its doing so, the
Title Company shall be entitled to tender into the registry or custody of any
court of competent jurisdiction all money or property in its hands under this
Agreement, together with such legal pleadings as it deems appropriate, and
thereupon be discharged from all further duties and liabilities under this
Agreement.

      11.20. Further Assurances. The parties agree to do such other and further
acts and things, and to execute and deliver such reasonable instruments and
documents, as either may reasonably request from time to time, whether on or
after the Date of Closing, in furtherance of the purposes of this Agreement. The
provisions of this Section 11.20 shall survive the Closing.

      11.21. Intentionally Omitted.

      11.22. Air Rights Lease. It is the Seller's and Purchaser's intention
after the Date of Closing to attempt, without any duty to pay any monies or
incur any liability in obtaining such consent, to obtain the consent of the MTA
to an assignment by Seller to Purchaser of Seller's interest as tenant under the
Air Rights Lease. In the event consent is obtained in a manner which does not
modify any of the terms and provisions of the Air Rights Lease, or on such other
terms as Purchaser may approve in its sole discretion, provided the same does
not create or impose any liability or obligation on Seller and provides for a
release of Seller in accordance with the Air Rights Lease as it exists on this
date, Seller, within thirty (30) days thereafter (such date to be established by
written notice by either party to the other setting a date not less than seven
(7) days after the date of such notice) (the "Assignment Closing Date") shall a)
assign the Air Rights Lease to Purchaser, b) convey fee simple title to the
Adjoining Parcel, the legal description of which is attached hereto as Exhibit
11.22-1, and c) deliver a deed of the structure of the Garage (together the
"Transferred Interests"). Seller and Purchaser agree to cooperate with one
another in seeking such consent, and in furtherance thereof shall advise the
other prior to engaging in discussions with the MTA and jointly determine the
impact of other parties' participation in any such discussions. Other than


                                      -26-
<PAGE>

incidental costs and expenses, such consultant's and attorneys fee's, neither
party shall be obligated to incur any cost or expense in such efforts.

      Five Million Dollars ($5,000,000) (the "Escrowed Sum") shall be deposited
in escrow with the Title Company on the Date of Closing. In the event the
consent of the MTA is obtained on the terms set forth above within four (4)
years of the Date of Closing, the Escrowed Sum shall be paid to Seller on the
Assignment Closing Date. If, at the expiration of said four (4) year period the
consent has not been obtained on the terms set forth above, the Title Company
shall return the Escrowed Sum, together with any remaining accrued interest
thereon, to Purchaser. After such four (4) year period, Seller shall have no
further obligation to seek the consent of the MTA but if such consent is
obtained, Seller shall assign its interest in the Air Rights Lease in accordance
with this Paragraph 11.22, provided Seller is reimbursed its costs and expenses,
including, without limitation, reasonable attorneys' fees, in connection
therewith. Interest earned on the Escrowed Sum shall be paid to Purchaser on a
quarterly basis. Notwithstanding the foregoing, if at the expiration of the four
(4) year period a good faith dispute exists as to whether the consent of the MTA
has been obtained in conformity with this Section 11.22, the four (4) year
period referenced above shall be extended until final resolution of such
dispute. Executed originals of the documents listed in Sections 11.22(d) and (e)
shall similarly be placed in escrow with the Title Company on the Date of
Closing and released on the Assignment Closing Date. On the Date of Closing
Seller and Purchaser shall enter into an escrow agreement in the form of Exhibit
11.22-2. The following provisions shall apply to the conveyance of the
Transferred Interests.

      a. Closing. The Closing with respect to the Transferred Interests will
take place pursuant to an escrow closing on the Assignment Closing Date at the
offices of the Title Company in Boston, Massachusetts, or, at Seller's option,
at the offices of Seller's attorneys at 10:00 a.m. Eastern Time or at such other
time and place as may be agreed upon in writing by Seller and Purchaser.

      Seller and Purchaser intend that the provisions of this Section 11.22
shall not be subject to the Rule Against Perpetuities or any rule of law with
respect to restriction on the alienation of property or remoteness of vesting of
property interests, and each of the Seller and Purchaser hereby agrees that it
will not make any contrary assertion or seek the benefit of the Rule Against
Perpetuities or other such rule of law, in any dispute arising under this
Section 11.22. In the event, however, that the Rule Against Perpetuities, or
similar rule of law shall limit the time within which any right or obligation in
this Section 11.22 may be valid or enforceable, then such right or obligation
shall be valid and enforceable only within the period of time commencing on the
Date of Closing hereunder and terminating on the date which is twenty-one (21)
years from the date of death of the last surviving child, grandchild,
great-grandchild and great-great-grandchild, in life as of the Date of Closing
hereunder, of Rose Fitzgerald Kennedy and The Honorable Joseph Patrick Kennedy,
late Ambassador to the Court of St. James.

      b. Operations Pending Closing. Prior to the Closing on the Assignment
Closing Date, the terms of the Sublease shall govern the operations of the
Sublease Premises. In addition thereto, Purchaser hereby agrees to assume full
care, custody and control of and


                                      -27-
<PAGE>

responsibility for the proper maintenance, repair and operation of the Adjoining
Parcel and to pay any and all costs associated therewith including without
limitation, liability insurance and real estate taxes, to the same manner and
effect as if it were a part of the Sublease Premises. Purchaser shall maintain
liability insurance on the Adjoining Parcel in the same amounts required of
Purchaser under the Sublease, such insurance to name Seller as an additional
insured and to otherwise meet the requirements of the Sublease. Purchaser shall
keep all driveways open and accessible and in good repair and shall perform all
obligations imposed under any and all easements, restrictions and covenants of
record, including without limitation the YMCA Easement Agreement.

      In recognition of the responsibilities assumed by Purchaser under the
Sublease and hereunder, Purchaser agrees that it will accept the Transferred
Interests in its As Is, Where Is then condition with all faults and
notwithstanding the physical condition thereof. Seller's representations and
warranties set forth in Section 5.1 of this Agreement shall be applicable to the
Transferred Interests only until the Date of Closing referred to in Section 2.3
and shall survive only for the period of time specified in Section 5.9. None of
said representations and warranties shall revive or be applicable to or
effective upon the transfer of the Transferred Interests or be a condition to
Purchaser's obligation to accept the Transferred Interests. Notwithstanding the
foregoing, the continuing accuracy of the representations and warranties of
Seller set forth in Sections 5.1.1, 5.1.2, 5.1.3 and 5.1.4 shall be a condition
to Purchaser's obligation but shall not survive the Assignment Closing Date.

      c. Title. Purchaser shall accept title to the Transferred Interests
subject to the Permitted Encumbrances, the Easement and Facilities Agreement,
the Easement Agreement and any and all other matters except liens or
encumbrances which were created after the Date of Closing by Seller or first
arose after the Date of Closing as a result of any action or inaction of Seller
(all of which Seller hereby covenants to cause to be released or removed), but
expressly excluding those arising because of any action or inaction of
Purchaser.

      d. Closing Deliveries by Seller. Seller shall deliver the following
original documents, each executed and, if required, acknowledged:

      (i)   Transfer of Seller's Interest in the Air Rights Lease and Deed to
            Adjoining Parcel and Garage structure in the form attached hereto as
            Exhibit 11.22-3, as the same may be modified to accommodate any
            changes requested by the MTA which do not affect the liabilities and
            obligations of Seller or Purchaser.

      (ii)  A termination of the Sublease in recordable form.

      (iii) A parking sublease of the Retained Spaces (as defined in the
            Sublease) in the form of Exhibit 11.22-4 attached hereto (the
            "Parking Space Sublease") and a recordable notice thereof.

      (iv)  Evidence satisfactory to the Title Company that all necessary
            approvals and/or consents by Seller and any constituent person or
            entity of Seller otherwise required under Seller's organizational
            documents have been delivered, and such other evidence reasonably
            satisfactory to the Title Company of Seller's


                                      -28-
<PAGE>

            authority and the authority of the signatory on behalf of Seller to
            execute the respective documents; and

      (v)   An Assignment to Purchaser of all permits and licenses applicable to
            or appurtenant to the Sublease Premises and Adjoining Parcel in the
            form attached hereto as Exhibit 11.22-5.

      (vi)  A recordable memorandum of Purchaser's rights set forth in this
            Paragraph 11.22, provided the Escrowed Sum shall not be disclosed.

            Seller shall re-execute any of the foregoing documents if required
            by the Title Company or if necessary to properly record those
            documents which are to be placed of public record in accordance with
            the Escrow Agreement. Seller shall execute such other ancillary
            documents (including, but not limited to any notices required to be
            given to the MTA under the Air Rights Lease) necessary for the
            consummation of the transaction contemplated in this Section 11.22
            provided that no such ancillary documents shall require Seller to
            pay any money or incur any liability.

      e.    Closing Deliveries by Purchaser's.

      (i)   Purchaser shall execute any agreements referred to in paragraph (d)
            above requiring execution by Purchaser; and

      (ii)  Purchaser shall execute such other documents as may be reasonably
            required by the Title Company.

            Purchaser shall re-execute any of the foregoing documents if
            required by the Title Company or if necessary to properly record
            those documents which are to be placed of public record in
            accordance with the Escrow Agreement. Purchaser shall execute such
            other ancillary documents (including, but not limited to any notices
            required to be given to the MTA under the Air Rights Lease)
            necessary for the consummation of the transaction contemplated in
            this Section 11.22 provided that no such ancillary documents shall
            require Purchaser to pay any money or incur any liability.

      f. Risk of Loss. Purchaser assumes all risk of loss with respect to the
Transferred Interests from and after the Date of Closing referred to in Section
2.3 and any loss as a result of casualty, taking or otherwise shall not affect
Purchaser's obligations hereunder.

      g. Closing Costs. The provisions of Section 6 above shall be applicable to
the Closing with respect to the Transferred Interests.


                                      -29-
<PAGE>

      h. Specific Enforcement. The obligation of Seller and Purchaser to
complete the assignment of Seller's interest in the Air Rights Lease in
accordance with this Paragraph 11.22 shall be specifically enforceable.

      i. Survival. The provisions of this Section 11.22 shall survive the Date
of Closing.


                                      -30-
<PAGE>

            IN WITNESS WHEREOF, Purchaser and Seller have executed this
Agreement on the date set forth below, effective as of the date set forth above.

                                SELLER:

                                JOHN HANCOCK LIFE
                                INSURANCE COMPANY


                                By:
                                    ----------------------------------------
                                    Name:  Paul M. Crowley
                                    Title: Vice President

                                PURCHASER:

                                BEACON CAPITAL STRATEGIC
                                PARTNERS II ACQUISITION, LLC


                                By:
                                    ---------------------------------------
                                    Name:  Fred A. Seigel
                                    Title: President and Chief Operating
                                           Officer


                                      -31-
<PAGE>

                                    EXHIBITS
                                    --------

EXHIBIT 1.1.1     Legal Description
EXHIBIT 1.1.3     Form of Easement and Shared Facilities Agreement
EXHIBIT 1.1.3-1   Form of Easement Agreement
EXHIBIT 1.1A      Form of Sublease
EXHIBIT 1.1.5     Inventory of Personal Property
EXHIBIT 1.1.8     Schedule of Leases and Deposits
EXHIBIT 1.1.10    Form of Naming Agreement
EXHIBIT 3.3       Schedule of Contracts
EXHIBIT 3.4.9     Form of Affiliate Lease
EXHIBIT 4.4       Tenant Obligations
EXHIBIT 4.5       Ongoing Capital Projects
EXHIBIT 4.6       Form of Tenant Estoppel Certificate
EXHIBIT 4.6-1     Form of Seller Estoppel Certificate
EXHIBIT 5.1.6-1   Notices of Defaults
EXHIBIT 5.1.6-2   Schedule of Tenant Arrearages
EXHIBIT 5.1.10    List of Brokerage Agreements
EXHIBIT 5.1.11    Schedule of Equipment Leases
EXHIBIT 5.1.12    Notices of Litigation
EXHIBIT 9.2.1     Statutory Quitclaim Deed
EXHIBIT 9.2.3     Bill of Sale
EXHIBIT 9.2.4     Assignment and Assumption of Leases
EXHIBIT 9.2.5     Assignment and Assumption of Contracts, Warranties and
                  Guarantees
EXHIBIT 9.2.7     Assignment and Assumption of PIC License
EXHIBIT 9.2.8     Form of Master Lease
EXHIBIT 9.2.11-1  Form of Seller's Air Rights Lease Estoppel Letter
EXHIBIT 9.2.11-2  Form of Seller's Sublease Estoppel Letter
EXHIBIT 9.2.13    Affidavit Pursuant to Foreign Investment and Real Property
                  Tax Act
EXHIBIT 9.2.21    Form of Section 6045 Designation
EXHIBIT 9.2.25    Form of Notice to MTA of Leasehold Mortgage
EXHIBIT 11.22-1   Adjoining Parcel Legal Description
EXHIBIT 11.22-2   Form of Escrow Agreement
EXHIBIT 11.22-3   Form of Assignment of Air Rights Lease and Deed to Garage
                  Structure and Adjoining Parcel
EXHIBIT 11.22-4   Form of Parking Space Sublease
EXHIBIT 11.22-5   Form of Assignment of Permits and Licenses Appurtenant to
                  Sublease Premises and Adjoining Parcel

      The above schedules and exhibits are not included herein. The Registrant
      hereby agrees to furnish to the Commission, supplementally, a copy of any
      omitted schedule or exhibit upon request.


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